1. Field of the Invention
This invention relates to an improved hand-held nebuliser by which patient inhalation causes a fine mist of fluid medication to be generated and mixed with a non-medicated ambient air supply so that the medication within the resultant composite nebulised air stream can be quickly and efficiently delivered to the respiratory tract of the patient through the deep lung.
2. Background Art
Breath inhalers are generally known by which ambient air inhaled by a patient through a mouthpiece can be mixed with particulate medication so that the medication can be quickly delivered into the blood stream of the patient without the use and accompanying inconvenience of a syringe. In the case of a nebuliser, fluid medication is commonly deposited on the back of a membrane. The membrane is then vibrated at a very high frequency to cause a jet effect which pulls the medication, in the form of a fine mist of droplets, through holes in the membrane.
However, it has been found that if the nebuliser is tilted or if the patient's head is not pulled back far enough, the fluid medication will run (under the influence of gravity) off the membrane. Similarly, if the patient is bedridden or if a complex air path must be established through the nebuliser, little medication will be nebulised to reach the bloodstream of the patient.
Accordingly, it would be preferable to have available an improved inhalation sensitive nebuliser, the use of which is independent of its alignment with in the patient's head so as to maximize the percentage of medication which reaches the deep lung of the patient. It would also be preferable that the improved nebuliser accept a standard, disposable fluid medication cartridge containing a liquid pharmaceutical. In this regard, it is desirable that the patient be able to dispense a precisely metered dose of fluid medication from the cartridge to the membrane so that a nebulised medication plume can be generated and mixed with a non-medicated stream of ambient air in synchronization with the inhalation of the patient.
Reference may be made to U.S. Pat. No. 5,152,456 issued Oct. 6, 1992 which provides one example of a nebuliser device.